1. Field of the Invention
This invention relates to a device for reducing toxic wastes of diesel fuel and more particularly, to a novel-type device for reducing toxic wastes of diesel fuel. The device of this invention, being equivalent to a pre-treatment device, is mounted to the surface side of a fuel feed port at a diesel internal combustion engine so as to activate molecules in diesel fuel and their molecular movement. In particular, with a view to effectuate induction of electromagnetic wave and magnetic field, some supplemental equipment such as a magnet, ceramic pole and coil are arranged on the device of this invention and based on this fabrication, perfect combustion conditions of diesel fuel may be provided in such a manner that some physicochemical changes are offered to diesel fuel, passing through the fuel feed port. Thus, the device of this invention has advantages in that a) after diesel combustion, the release of toxic substances in exhaust gas may be significantly inhibited, and b) fuel consumption may be further improved.
2. Description of the Prior Art
A process of forming toxic substances from exhaust gas of diesel fuel is summarized as follows: when combustion from a diesel engine is under way, air and diesel fuel are partially mixed during their reaction. The reaction between air and diesel fuel is carried out in a series of sequential processing steps--mixed gas formation, ignition, combustion and explosion--that influence each other. In this context, since the concentration ratio of mixed gas and air is not constant, combustion occurs at one point, while a heating process, such as vaporization, is performed at another point in the process.
When heating some rich areas in the reaction band of both diesel fuel and air, the reaction is carried out from vapor pocket at the surface of fuel particles and then carbon particles from the hydrocarbons are isolated. If the ignition of isolated carbon particles is blocked by such reaction, the particles are released into air in the form of soot without combustion. Some gaseous toxic wastes including soot are released together with CO, HC, NOx and SOx. In particular, since combustion in a diesel engine does not occur in the presence of excessive air, the amount of CO released is not serious but non-firing hydrocarbons generated from a low-load and/or cold driving have imposed serious problems to the environment.
As such, some particle substances released from diesel engine are environmental contaminants; for example, the soot may irritate eyes and have a bad odor, among other things. Further, while still in dispute, the aromatic hydrocarbons absorbed in the soot may affect the human body. At any rate, if the soot is inhaled into the human's respiratory tract, undesirable effects may occur.
When some problems associated with normal and abnormal combustion from a diesel engine are reviewed mechanically and chemically, the combustion from a diesel engine occurs in such a manner that, unlike a gasoline engine, the injection of diesel fuel continues for a certain period. Thus, the intervals of fuel injection will significantly affect some fuel combustion. In general, a diesel engine is characterized in that, through a compression stroke of air, injected fuel within a cylinder is formed into an appropriately mixed gas and ignited spontaneously. Thus, several flame nuclei are simultaneously formed, while the combustion occurs throughout the cylinder.
FIG. 1 contains a graph showing the combustion process of a diesel engine. When diesel fuel is injected at "A" point, an ignition lag occurs between points "A" and "B", normally an extremely short time due to heating and chemical change. Hence, if the ignition lag is long, the maximum explosion pressure is high, as illustrated in FIG. 2. If the ignition lag is, on the contrary, short, the injection fuel is slowly fired in the sequential order of injection. Then, since the pressure within the cylinder builds slowly, the highest explosive force is maintained by the pressure formed within a cylinder. Therefore, if the ignition lag is short, a maximum explosion pressure is lower than FIG. 2, as shown in FIG. 3.
Since diesel fuel within a diesel engine is fired under constant pressure, a slow combustion process is required. If diesel fuel having a long ignition lag is employed, the drastic combustion causes a diesel knock phenomenon under the reversed constant-pressure combustion. Since an explosive pressure is rapidly enhanced simultaneously with ignition between "B" and "C" illustrated in FIG. 1, diesel fuel accumulated between "A" and "B" is continuously exploded simultaneously with ignition. This is a change corresponding to the basic-cycle static combustion and cannot be regulated by any other method from the outside.
Since the pressure and temperature within a combustion chamber may adequately reach the necessary levels between "C" and "D" as illustrated in FIG. 1, injected diesel fuel is fired in a sequential order of injection and the process is maintained in nearly constant pressure. However, if such period gets much longer, the cut-off ratio of diesel fuel becomes enlarged and its thermal efficiency lowered. In order to ensure the maximum efficiency with high output within a limited cylinder, it is considered that the maximum combustion effects should be fulfilled by a minimum amount of excessive air with an appropriate mixing ratio of injection fuel, atomization and air.
Further, some remaining fuel, which has not been fired at the point of "D" illustrated in FIG. 1, maintains the after-burning state but this is of little help in that such fuel increases the temperature of combustion exhaust and blackens the color of exhaust gas. Such phenomenon occurs because diesel fuel having a long ignition lag is used and there is an accumulation phenomenon with the fixed fuel valve reopened.
As mentioned above, diesel knock is not responsible for thermal damages due to abnormal heat transmission but a sharp fluctuation in torque may not provide any quiet driving and also, there is a risk that its impact will result in causing an excessive stress (Automobile Engineering, Won Sup Bae, 1992, Dongmyung Publication Co., pp. 222-230; Diesel Engine, Eung-Suh Kim, 1996, Semoon Publication Co., pp. 367-370; Automobile Engine II diesel engine, Jae-Hwi Kim, 1997, Choongwon Publication Co., pp. 442-444.).
Unlike a gasoline engine, a diesel engine has an unclear limitation on the diesel knock phenomenon which may be underestimated. Basically, it is possible to avoid the diesel knock with a short ignition lag. As such, since the ignition lag causes diesel knock, it is imperative that to prevent such phenomenon, diesel fuel having better ignition property should be used and, otherwise, proper alternatives be instituted.
To overcome the combustion related problems associated with a diesel engine, such factors as compression ratio and suction/ cylinder temperature should be considered. Hence, it is preferred that the temperature of compression and suction is higher, since this means that higher compression is given to the air inhaled into a combustion chamber.
Under such state, the fluidity of air intake and proper time of injecting diesel fuel should be determined. A swirling or turbulent flow of air-intake will facilitate the chemical reaction during the mixing process. Moreover, if an air-intake temperature is high, vaporization of diesel fuel is increased which helps to atomize the injected diesel oil, thus shortening the ignition lag. Also, if the injection period of fuel is determined as a top dead center, its mean temperature and pressure are maximized so that the ignition lag is further shortened.
However, since a machine has a limit, the mechanical limit should be necessarily overcome by shortening the ignition lag period through proper control of appearance or nature of the diesel fuel. The ignition lag period is one of the critical problems affected by diesel fuel. At this point, with reference to the appearance and nature of diesel fuel, including the process of atomization and dispersion, the possible notion is that since diesel fuel having higher firing temperature is responsible for longer ignition lag, diesel fuel of many cetane numbers should be used, and atomized dispersion should be mechanically considered so that injected fuel is in broad contact with high-temperature air. In addition, the following regulation method is considered in solving the problems associated with the properties of diesel fuel in terms of its physicochemical causes.
First, when the viscosity of diesel fuel is reviewed, the viscosity of hydrocarbons is enhanced proportionately with the increase of carbon numbers. If the carbon numbers are the same, the viscosity of naphthene series is higher than that of olefin or paraffin series. In general, if the boiling point of diesel fuel is low, its viscosity is also low. Also, the viscosity of diesel fuel has a close relationship with atomization; if the viscosity of diesel fuel is low, its enhanced dispersing property and particulated dispersion facilitate the heating and vaporization, thus shortening the ignition lag and improving the combustion. However, if the viscosity of diesel fuel is extremely low, its weak through-force within a combustion chamber results in losing the homogenous distribution of diesel fuel within a cylinder and a poor contact with air is also responsible for inhomogeneous combustion. In addition, a poor lubrication is caused by an injection pump or injection nozzle and there is a high risk on the leakage of diesel fuel. In contrast, if the viscosity of diesel oil is much higher, the residues are accumulated on the internal engine, thus generating smoke and bad odors.
In case of diesel fuel having varying viscosity in terms of its nature, a fuel temperature should be maintained at a certain level. Therefore, it is generally stipulated that the viscosity of diesel fuel be 2.about.5.8 nwl.sup.2 /s at 30.degree. C. or 37.8.degree. C. Nevertheless, as mentioned above, it is imperative that diesel oil should be provided with the following conditions, such as guaranteed through-force, better dispersion and enhanced particulation.
Second, diesel fuel should have better ignition property so as to ensure normal combustion without diesel knock in a diesel engine. In general, a cetane number is mentioned for specifying the firing property. It is stipulated that the cetane number of a high-speed diesel engine fuel be more than 45 at minimum. If any diesel fuel has many cetane numbers, better improved starting point contributes to more efficient driving. However, if any diesel fuel has a great number of cetanes, there will be larger portion occupied by normal paraffin-based hydrocarbons and then, lower density and viscosity will be responsible for a weak penetration of injected fuel, thus resulting in imperfect combustion.
Third, with reference to the formation of soot, there is an increasing trend for soot release, when diesel fuel has a more compact molecular structure. Namely, the trend for soot release becomes higher in the sequential order of paraffin, naphthene and aromatic series.
As shown in the following chemical formula 1, normal paraffin has a hydrocarbon-bonded linear chain type (direct chain type) with a molecular formula of C.sub.n H.sub.2n+2.
Chemical formula 1 ##STR1##
Also, as shown the following chemical formula 2, naphthene series consist of ring-shaped and single-bonded hydrocarbons structure with a molecular formula of C.sub.n H.sub.2n. Its structure is chemically stable since there is no double bonding.
Chemical formula 2. ##STR2##
Further, as shown the following chemical formula 3, aromatic series consist of ring-shaped and double-bonded hydrocarbons structure. Its basic structure is a three-double bonded benzene ring with 6 carbon atoms. Several other molecules may be bonded to benzene ring, while its ignition property is low and anti-knock is strong.
Chemical 3. ##STR3##
As noted in the above chemical formulae 1, 2 and 3, it is assumed that the molecular structure of carbon may be a factor in producing the soot during the combustion of diesel fuel.
Further, the majority of solid particle substances of diesel fuel released by combustion is in the range of about 0.01-10 .mu.m in diameter. Thus, some solid particle substances of soot whose mean mass has a particle size of less than 1 .mu.m in diameter should be separated prior to combustion, the appearance of diesel fuel should be also controlled. As observed from the above results, the formation of such solid particle substances is due to the chemical reaction of hydrocarbons.
In the meantime, with reference to some hydrocarbon of diesel fuel similar to that of the chemical formula 2 and chemical formula 3, carbon particles from the hydrocarbon are isolated during heating reaction in a pocket at the surface of fuel particles and when the reaction is continuously made, the combustion of these carbon particles are blocked and non-firing carbon particles are released into air in the form of soot. With carbon particles isolated, the blocked combustion of isolated carbon particles may be explained by the above mentioned facts but another factor is that among the ring-shaped hydrocarbons, molecular structures of the chemical formulae 2 and 3, hydrogen is isolated only when double-bonded molecular structure of carbon is not degraded; then, due to various reasons, such as combustion in insufficient oxygen during combustion and operating conditions of internal diesel engine, some solid particle substances are formed and released in the form of soot.
As aforementioned, any possible hypothesis based on viscosity, firing property and formation of soot is that to comply with some conflicting problems of diesel fuel, better injecting property should be provided and at the same time, its ignition property is higher; in addition, some solid particle substances generated by diesel fuel should be eliminated.
In light of the aforementioned aspects, the following matters should be considered so as to reduce the formation of soot from a diesel internal combustion engine and to improve the combustion efficiency intended for saving fuel consumption.
First, it is a dry air inhaled from the atmosphere to a diesel engine. Namely, the chemical composition of dry air comprises 78 vol % (75 wt %) of nitrogen (N.sub.2) and 21 vol % (23.2 wt %) of oxygen (O.sub.2). When dry air including nitrogen and oxygen is inhaled into a cylinder and compressed under higher pressure, some measures should be taken to have oxygen immediately react with diesel fuel under vaporization of hydrocarbons for oxidation thereof, without having the oxygen reacting with the nitrogen.
Second, some proper measures should also be established when hydrogen is isolated from carbon, in order that a) vaporized hydrocarbon may be reacted with oxygen, and b) perfect combustion may be made available by proper reaction among hydrogen, carbon and oxygen.
Therefore, this inventor has made extensive studies to overcome the above several problems and completed this invention which may inhibit the release of gaseous toxic wastes and particulated toxic wastes and at the same time, may improve the fuel consumption. This invention is characterized in that a) to improve combustion conditions of diesel fuel when supplied from a fuel tank to a fuel feed hose or pipe, lots of hydrocarbons (a mixture of hydrocarbons having about 10.about.20 carbons boiled at about 170.about.370.degree. C.) in the diesel fuel are induced by an electromagnetic regulation method to achieve a molecular nature that is nearly adequate for perfect combustion, b) for further effective combustion, oxygen in the inhaled and compressed air is controlled by an electromagnetic regulation method from an air intake hole, c) under excess of air, solidified particle carbons owing to insufficient oxygen, and d) carbons may be sufficiently reacted with oxygen in any reaction band.